Roller-core drill



L. H. WELLENSIEK ROLLER CORE DRILL Filed Aug] 2, 1925 Feb. 24, 1931.

Patented Feb. 24, 1931 UNITED STATES PATENT OFFICE LOUIS H. WELLENSIEX, or HoUsToN, TEXAS, AssIeNoR To HUGHES Toon coMrANY, or HoUsToN, TEXAS, A CORPORATION or TEXAs ROLLER-CORE DRILL Application led August 2, 1926. Serial No. 126,470.

My invention relates -to core drills for use particularly in hard formation and having rolling cutters thereon..

Core drills have been constructed before with rolling cutters thereon arranged to cut an annular hole about the core, but although some such drills will cut the formation, eX- perience has shown that a good core cannot be thus obtained with the old type of roller core drill. The reason is thatthe rolling cutters cause a large amount of vibration and side sway of the drill head in performing the cutting operation, and the core is broken up and worn away to such an eX- 16 tent that it cannot be engaged by the core catcher and removed with the bit from the hole.

It is an object of my invention to provide a roller core drill, on which the cutters are so mounted that there will be a minimum of vibration, thus leaving a full sized unbroken core which can be readily removed.

It is desired that the cutters be mounted to cut the wall of the hole smoothly and evenly and to cut a clearance about the core so that the drill will work straight in the hole and not stick in the formation as in order to present the cutters in the proper manner a special construction of the head,

pins and attaching means is required. The manner of mounting the cutter shafts is also a feature of value.

Referring to the drawing herewith. Fig. 1 is a side elevation of a drill bit equipped 36 with my invention, parts being broken away in central longitudinal section. Fig. 2 is a bottom plan view and Fig. 3 is a broken enlarged section on the plane 3 3 of Fig. 2. Fig. 4 is a transverse section through a hole being drilledshowing: diagrammatically the zones traversed by the inner and outer cutting rollers and also the inclination of the axes of the cutters from a horizontal plane. Like. numerals of reference are employed to designate like parts in all the views,

The head 1 of my drill is a tubular body having a threaded box 2, at the upper end to connect with a drill collar 3 for operation. The interior of the head is threaded at 4 to recelve the collar 5 of a core barrel 6.

Below the core barrel the inner wall'of the head 1s tapered downwardly to provide a seat 7 for the core catcher 8. Said core catcher has toothed jaws thereon to engage and hold the core when the drill is elevated. vlili My invention lies particularly in the arrangement and form of the cutters. I ar-` range the said cutters in sets of three, and this 1s a most important feature in that it glves for each set of cutters a three point support which prevents vibration. There are three cutters 9 to cut the inner wall of the hole. They are arranged symmetrically 1n radial position on the head and rotatable y on pins 10 which, as shown in Fig. 1, are in- 65 clined slightly upwardly toward the center of the bit. The head 1 has a specially constructed lower face 25. This face is formed into six almost distinct segments 26 and 26 which are separated by the grooves 21. Each alternate segmentis identical as'there are three segments 26 for the inside cutters` 9 and three segments 26 for the outside cutters 13, as best seen in Fig. 2. The segments 26 each have an inverted U shaped kerf 28 formed centrally thereof and opening in from the bottom. These kerfs each have'a sloping surface 29 which merges with a shoulder 30. The segment 26 also has formed therein an outwardly sloping pocket or slot 19 which is spaced radially inward from the kerf 28; said pocket is constructed in the head so that it leaves but a very thin supporting portion 32 which terminates short of the lower face 25.

The pins 10 have only one support on the lower side and that is at the outer end which is provided with a flange 11 the outer portion of which is reduced in diameter. The

iange 11 is adapted to accurately seat upon 90 Arolling motion.

the shoulder 30 in order to obtain correct placement of the cutter 9. After the pin 10 has been thus located the space about the pin in the kerf 28 is filled with welding materlal 12 so that the pin is thereafter internally attached to the segment 26 of the head 1. At the inner end of the pin 10 the sup-4 porting portion 32 is adapted to form a bearing seat about substantially one-half of the pin as seen in Fig. 1. In this manner the pin 10 carrying the cutter 9 is arranged to withstand the enormous loads which are imposed upon it in present day drilling operations. There is little or no downward pull upon the cutters or pills so that when the pin is seated at 32 and located in the kerf with the bond l2 of welding material it is secured firmly in the head.

The cutters 9 are rotatable in slots 19 in the head and have a bearing on the inner cylindrical end of the pin. They have a tapered periphery to engage and cut the formation. The taper ofthe cutters is such as to bring the apex at the central axis of the hole, so that said cutters will have a true The outer cutters 13 are mounted in a similar symmetrical position radially of the head. They are rotatable on pins 14,-see Fig. 3- which are inclined downwardly toward the center. These pins 14 are firmly retained by the segment 26 which is formed somewhat like the segment 26 but with the structure reversed as the slots or pockets 18 slope inwardly. An inverted U shaped kerf 28 is formed in the outer surface of the segment and has a sloping surface 29 and shoulder 30, the same as the construction 'for ,the inwardly sloping cutters 9. The `pin 14 thus is adapted to be secured firmly in the kerf 28 by means of the welding material 16. The outer end of the pin 14 has a flange 15 fitting within a recess 40 in the cutter and also adapted to seat on the shoulder 30. The extreme outer end of the pin 14 is reduced to form a larger bonding surface in addition to the sloping face 29', and aI bond 16 of welded material above said flange fixes the pin in the head.

The means used to secure the inner ends yof the pins 14 is somewhat different from that of the alternate pins 10. I have resorted to this difference as the outer cutters are subjected to greater stresses and torque and travel at a greater speed than the inside cutters. The segment 26 as recited has the pocket 18 therein but a substantial portion of the segment remains as at 41, Figs. 2 and 3; said portion adjacent its base has a circular opening 17 therein which is formed at the proper inclination to receive the pin 14 when the flange 15 is properly seated at 30. The pin 14 is preferably beveled as at 42 so that proper clearance may be had for the loose material from the cutters 9.

The cutters 13 are of larger diameter than the cutters 9 and are toothed to cut the material and are tapered and positioned to produce a true rolling motion. The said cutters 13 ft in slots 18 in the head which serve to house the upper sides of said cutters.

The flushing water is discharged directly cut the outer part of the hole and provide clearance for the cutter pins 10 and their supports. L

A core drill, constructed as set out above, works smoothly and evenly and will take a full sized core without failure where the older types will rarely, if at all, bring out a core. This is due to a combination of two features; the symmetrical three-point support, and the tapering and mounting of the cutters to give them a true rolling motion.

The present core bit has been evolved as the result of much experimentation and the means and method of securing the pins and cutters to the head has been resorted to only because sufficient clearance and rigidity are then obtainable.

In operation, the bit is rotated to roll the cutters upon the bottom of the hole. 'Ihe inner set of cutters cuts an annular track around the core, and being supported at three evenly spaced points, they roll without vibration. The outer set of three also cuts an annular track about the outer side of the hole, the two tracks cut by the different sets forming an annular path extending inwardly and upwardly as clearly shown in Fig. 4. The flushing water washes the cutters free of material which is carried upwardly through grooves 2l on the outer face of the head, and around the drill stem to the surface.

Having thus described the invention, what I claim as new and desire to protect by Letters Patent is:

l. A roller core drill including a tubular head, a set of three symmetrically arranged inwardly tapered roller cutters mounted on the faire of said head on shafts upwardly and inwardly inclined to forni a bias cut, a second set of three symmetrically arranged inwardly tapered roller cutters mounted in said head intermediate the first set and radially outward relative thereto, said second set of cutters being disposed on shafts inclined up` wardly and outwardly of the head, and means to integrally secure said shafts to said head the first mentioned cut.

interior of the p ters forming the inner face.

usadas 2. In a roller coring bit, a head, a plurality fo radial segments thereon, a pocket in eac of said segments, a cutter dis osed in each of said pockets, a shaft upon which said cutter is rotatable, a kerf in said segment, a shoulder in said kerf, a flange on said shaft adapted to seat on said shoulder. welded material littng said kerf and integrally bonding said pin and said segment.

3. A roller core drill including a tubular head, a plurality of inwardly tapered roller cutters arranged for true rolling cutting action having axes inclinedVwit-lx respect to the axis of the head and cutting edges inclined to cut angularly related surfaces for the hole, the axis of each cutter forming one surface being differently inclined toward the axis of the head than the axis of the cutter forming another surface, and means for integrally securing the cutters to the head within the path of the cut.

4. A roller core" drill including a tubular y head, two sets of three alternately s aced inwardly tapered roller cutters, eac arranged for true rolling cutting action, the axes of one set being inclined downwardly toward the axis of the head and the axes of the other inclined upwardly ltoward the axis of said head, and means integral with said head for supporting the rollers within the path of the cut.

wardly and upwardly inclined toward the axis of said head, a transverse bearing for each pocket lconfined within the side walls of the head, inwardly tapering roller cutters with .supporting shafts mounted in said pockets to take the' corresponding inclination and confined between the circular walls of said head, and said shafts bein secured to the bearings of the pockets by nds of metal welding.

In testimony whereof, I hereunto ailix my signature, this 26th da of July A. D. 1926. LOUISA WELLENSIEK.

5. A roller core drill including a tubular head,two sets of three alternately s ace'd inwardly tapered cutters each arrange for true rolling cutting action, pins for supporting said cutters each alternately inclined downwardly and upwardly toward the axis of the head, and means for integrally securin said pins to the head within the path of t e cut formed by the drill. I v

6. A roller core drill includinga tubular head, two sets of alternately spaced inwardly` tapering cutters arranged for true rolling cutting action, the axis of each alternate cutter being inclined downwardl and upwardly towardpthe axis of the hea to form the outer and inner faces of the hole respectively, and Y. the `set of cutters forming the outer face belng of a greater diameter than the set of cut- 7. A roller core drill including ing pockets alternatel h dh 1 l'ty ff filmhuis?" 'i' inclined downwaiidland upwardly tower the axis of said hea a transverse bearing for each pocket confined. within thek walls of the head, inwardly taperporting shafts 1 n pockets to takethe corre-1 ndmg mclinatxon and confined between 'circular walls of said head, and said i1-; shafts being secured to the bearingA of the' ing roller cutters with su mounted in said p s te pockets by bonds of metal welding.

8. A roller core drill-including a tubular-f head having 'l plurality of sets of three for f 'Y "i wardly opening pockets alternately `down- 

